Copper Chalcogenide Clusters Stabilized with Ferrocene-Based Diphosphine Ligands

The redox-active diphosphine ligand 1,1′-bis­(diphenylphosphino)­ferrocene (dppf) has been used to stabilize the copper­(I) chalcogenide clusters [Cu₁₂(μ₄-S)₆(μ-dppf)₄] (<b>1</b>), [Cu₈(μ₄-Se)₄(μ-dppf)₃] (<b>2</b>), [Cu₄(μ₄-Te)­(μ₄-η²-Te₂)­(μ-dppf)₂] (<b>3</b>), and [Cu₁₂(μ₅-Te)₄(μ₈-η²-Te₂)₂(μ-dppf)₄] (<b>4</b>), prepared by the reaction of the copper­(I) acetate coordination complex (dppf)­CuOAc (<b>5</b>) with 0.5 equiv of E­(SiMe₃)₂ (E = S, Se, Te). Single-crystal X-ray analyses of complexes <b>1</b>–<b>4</b> confirm the presence of {Cu_2<i>x</i>E_<i>x</i>} cores stabilized by dppf ligands on their surfaces, where the bidentate ligands adopt bridging coordination modes. The redox chemistry of cluster <b>1</b> was examined using cyclic voltammetry and compared to the electrochemistry of the free ligand dppf and the corresponding copper­(I) acetate coordination complex <b>5</b>. Cluster <b>1</b> shows the expected consecutive oxidations of the ferrocene moieties, Cu^I centers, and phosphine of the dppf ligand

Copper Chalcogenide Clusters Stabilized with Ferrocene-Based Diphosphine Ligands

The redox-active diphosphine ligand 1,1′-bis­(diphenylphosphino)­ferrocene (dppf) has been used to stabilize the copper­(I) chalcogenide clusters [Cu₁₂(μ₄-S)₆(μ-dppf)₄] (<b>1</b>), [Cu₈(μ₄-Se)₄(μ-dppf)₃] (<b>2</b>), [Cu₄(μ₄-Te)­(μ₄-η²-Te₂)­(μ-dppf)₂] (<b>3</b>), and [Cu₁₂(μ₅-Te)₄(μ₈-η²-Te₂)₂(μ-dppf)₄] (<b>4</b>), prepared by the reaction of the copper­(I) acetate coordination complex (dppf)­CuOAc (<b>5</b>) with 0.5 equiv of E­(SiMe₃)₂ (E = S, Se, Te). Single-crystal X-ray analyses of complexes <b>1</b>–<b>4</b> confirm the presence of {Cu_2<i>x</i>E_<i>x</i>} cores stabilized by dppf ligands on their surfaces, where the bidentate ligands adopt bridging coordination modes. The redox chemistry of cluster <b>1</b> was examined using cyclic voltammetry and compared to the electrochemistry of the free ligand dppf and the corresponding copper­(I) acetate coordination complex <b>5</b>. Cluster <b>1</b> shows the expected consecutive oxidations of the ferrocene moieties, Cu^I centers, and phosphine of the dppf ligand

SEARCH FOR GRAVITATIONAL-WAVE BURSTS ASSOCIATED WITH GAMMA-RAY BURSTS USING DATA FROM LIGO SCIENCE RUN 5 AND VIRGO SCIENCE RUN 1

We present the results of a search for gravitational-wave bursts associated with 137 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments during the fifth LIGO science run and first Virgo science run. The data used in this analysis were collected from 2005 November 4 to 2007 October 1, and most of the GRB triggers were from the Swift satellite. The search uses a coherent network analysis method that takes into account the different locations and orientations of the interferometers at the three LIGO-Virgo sites. We find no evidence for gravitational-wave burst signals associated with this sample of GRBs. Using simulated short-duration (<1 s) waveforms, we set upper limits on the amplitude of gravitational waves associated with each GRB. We also place lower bounds on the distance to each GRB under the assumption of a fixed energy emission in gravitational waves, with typical limits of D ~ 15 Mpc (E_GW^iso / 0.01 M_o c^2)^1/2 for emission at frequencies around 150 Hz, where the LIGO-Virgo detector network has best sensitivity. We present astrophysical interpretations and implications of these results, and prospects for corresponding searches during future LIGO-Virgo runs.Comment: 16 pages, 3 figures. Updated references. To appear in ApJ